Write TestRandom util (#976)

Signed-off-by: litt3 <[email protected]>

common/testutils/random/test_random.go

@@ -0,0 +1,55 @@
+package random
+
+import (
+	"fmt"
+	"math/rand"
+	"time"
+)
+
+// TestRandom provides all the functionality of math/rand.Rand, plus additional randomness functionality useful for testing
+type TestRandom struct {
+	*rand.Rand
+}
+
+// NewTestRandom creates a new instance of TestRandom
+// This method may either be seeded, or not seeded. If no seed is provided, then current unix nano time is used.
+func NewTestRandom(fixedSeed ...int64) *TestRandom {
+	var seed int64
+	if len(fixedSeed) == 0 {
+		seed = time.Now().UnixNano()
+	} else if len(fixedSeed) == 1 {
+		seed = fixedSeed[0]
+	} else {
+		panic("too many arguments, expected exactly one seed")
+	}
+
+	fmt.Printf("Random seed: %d\n", seed)
+	return &TestRandom{
+		rand.New(rand.NewSource(seed)),
+	}
+}
+
+// RandomBytes generates a random byte slice of a given length.
+func (r *TestRandom) RandomBytes(length int) []byte {
+	bytes := make([]byte, length)
+	_, err := r.Read(bytes)
+	if err != nil {
+		panic(err)
+	}
+	return bytes
+}
+
+// RandomTime generates a random time.
+func (r *TestRandom) RandomTime() time.Time {
+	return time.Unix(r.Int63(), r.Int63())
+}
+
+// RandomString generates a random string out of printable ASCII characters.
+func (r *TestRandom) RandomString(length int) string {
+	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	b := make([]byte, length)
+	for i := range b {
+		b[i] = charset[r.Intn(len(charset))]
+	}
+	return string(b)
+}

common/testutils/random/test_random_test.go

@@ -0,0 +1,27 @@
+package random
+
+import (
+	"github.com/stretchr/testify/assert"
+	"math/rand"
+	"testing"
+)
+
+// Tests that random seeding produces random results, and that consistent seeding produces consistent results
+func TestSetup(t *testing.T) {
+	testRandom1 := NewTestRandom()
+	x := testRandom1.Int()
+
+	testRandom2 := NewTestRandom()
+	y := testRandom2.Int()
+
+	assert.NotEqual(t, x, y)
+
+	seed := rand.Int63()
+	testRandom3 := NewTestRandom(seed)
+	a := testRandom3.Int()
+
+	testRandom4 := NewTestRandom(seed)
+	b := testRandom4.Int()
+
+	assert.Equal(t, a, b)
+}

common/testutils/test_utils.go

@@ -11,6 +11,7 @@ import (
 
 // InitializeRandom initializes the random number generator. If no arguments are provided, then the seed is randomly
 // generated. If a single argument is provided, then the seed is fixed to that value.
+// Deprecated: use TestRandom instead
 func InitializeRandom(fixedSeed ...uint64) {
 
 	var seed uint64
@@ -85,6 +86,7 @@ func ExecuteWithTimeout(f func(), duration time.Duration, debugInfo ...any) {
 }
 
 // RandomBytes generates a random byte slice of a given length.
+// Deprecated: use TestRandom.RandomBytes instead
 func RandomBytes(length int) []byte {
 	bytes := make([]byte, length)
 	_, err := rand.Read(bytes)
@@ -95,11 +97,13 @@ func RandomBytes(length int) []byte {
 }
 
 // RandomTime generates a random time.
+// Deprecated: use TestRandom.RandomTime instead
 func RandomTime() time.Time {
 	return time.Unix(int64(rand.Int31()), 0)
 }
 
 // RandomString generates a random string out of printable ASCII characters.
+// Deprecated: use TestRandom.RandomString instead
 func RandomString(length int) string {
 	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
 	b := make([]byte, length)